1. Field of the Invention
The present invention relates to adjustable beds and, more particularly, to articulated medical beds for use in the long term care and home care markets.
2. Description of the Prior Art
Bedridden individuals often develop blood circulation problems and commonly experience general discomfort from lying in a single planar position over extended periods of time. To facilitate the occupant""s care and comfort, medical beds are often designed to include distinct articulated support sections which are adjustable between a plurality of positions. The articulated sections typically provide for occupant positions ranging from a horizontal lying position to a contoured sitting position.
While articulated beds have found wide spread use in hospitals, nursing homes, long term care facilities and home care markets, such beds are usually expensive devices employing complicated adjustment mechanisms. An example of such an adjustable bed is disclosed in U.S. Pat. No. 4,395,786 to Casey et al. The bed in Casey et al. includes a complex linkage arrangement driven by two separate actuators for adjusting three articulated support sections. One actuator moves an articulated head section while a second actuator adjusts articulated foot and thigh sections. Accordingly, there is a need for an articulated medical bed of a simple design including multiple articulated support sections which are adjustable by a single actuator.
Another problem often associated with articulated medical beds is the length of the sleeping surface. Hospitals, nursing homes and long term care facilities typically cannot predict the height of their incoming patients or residents. These facilities often waste limited resources by purchasing a variety of beds having different sleeping surface lengths. Accordingly, there is a need for an articulated bed which may be easily and inexpensively altered to adapt its sleeping surface length to the height of its occupant.
It is well known in the art to use a safety side rail in conjunction with articulated medical beds. Such side rails are typically located adjacent to the sleeping surface and prevent the occupant from falling out of the bed. As disclosed in U.S. Pat. No. 3,823,428 to Whyte and U.S. Pat. No. 4,439,880 to Koncelik et al., side rails are often adjustable in a horizontal direction. However, the prior art side rails have limited adjustability in that they have positive stops only in a fully retracted or fully extended state. The occupant is often inadequately protected when the side rail is fully retracted in that a large opening exists through which the patient could fall. Conversely, the occupant is often unnecessarily confined when the side rail is fully extended. Accordingly, there is a need for an articulated medical bed including a adjustable side rail having intermediate positive stops between fully retracted and fully extended positions.
Articulated medical beds are typically adjusted by the occupant utilizing a controller for causing articulated movement of the support sections. The controller usually comprises either a hand-held push button or a push button embedded in one of the side rails of the bed. Patients will often lack the hand-eye coordination, finger dexterity or mental alertness required to operate the prior art controllers. Accordingly, there is a need for an articulated medical bed having a controller which facilitates operation by disoriented occupants or those lacking good coordination skills or finger dexterity.
The present invention provides an articulated medical bed of a simple structure including an articulated, variable length support frame which is adjustable by a single actuator activated by a control stick mounted to a telescoping side rail having intermediate positive stop positions.
In accordance with the present invention, an articulated medical bed is disclosed which includes an articulated support frame mounted to a base defined by a main frame. The support frame includes an upper body section, a seat section and a lower leg section. A pivot connection connects the upper body section to the main frame for pivotal movement of the upper body section relative to the base. A first end of the seat section is pivotally connected to an end of the upper body section while a second end of the seat section is pivotally connected to a first end of the lower leg section. Elongated link members have first ends pivotally connected to the main frame and second ends pivotally connected to a second end of the lower leg section. The lower leg section and the elongated link members are detachably mounted whereby the lower leg section is replaceable with another lower leg section having a different length. A glide member is mounted on the seat section and supported for linear movement along the base. The seat section is supported for rocking movement about the glide member in response to pivotal movement of the upper body section about the pivot connection. A linear actuator is connected to the upper body section for actuating the upper body section in pivotal movement. Upon pivotal movement of the upper body section, the seat section and lower leg section are simultaneously actuated for articulated movement.
A side rail is supported on the main frame and located adjacent to the support frame. The side rail includes vertical rail members extending above the support frame and horizontal rail members extending between the vertical rail members. The horizontal rail members comprise inner horizontal rail members received within outer horizontal rail members in a telescoping relationship whereby the inner horizontal rail members are mounted for movement relative to the outer horizontal rail members. One of the inner horizontal rail members defines a fully retracted position of the inner horizontal rail member relative to the outer horizontal rail member. A plurality of recesses are formed in one of the outer horizontal rail members for receiving a detent supported on one of the inner horizontal rail members. Engagement of the detent with one of the recessed portions locks the inner horizontal member relative to the outer horizontal member in either a fully extended position or a predetermined intermediate position between the fully retracted and fully extended positions.
Operation of the linear actuator is controlled by movement of a control stick supported on at least one of the vertical and horizontal rail members of the side rail. The control stick is preferably located within a side rail plane defined by the vertical and horizontal rails. Movement of the control stick in a first direction actuates the actuator for moving the upper body section upwardly while movement of the control stick in a second direction actuates the actuator for moving the upper body section downwardly. As the upper body section moves upwardly, the pivot connection between the upper body section and the seat section moves downwardly, while the pivot connection between the seat section and the lower leg section moves upwardly. As the upper body section moves downwardly, the seat section and lower leg section articulate in a reverse direction. The pivot connection between the seat section and the lower leg section is never lower than the pivot connection between the upper body section and the seat section such that the occupant""s feet are never lower than his hips thereby facilitating improved blood circulation.
Therefore, it is an object of the present invention to provide an articulated medical bed of simple design including a support frame having multiple articulated support sections which are simultaneously adjustable by a single actuator.
It is a further object of the invention to provide such an articulated medical bed wherein the support frame has an adjustable length.
It is yet another object of the invention to provide such an articulated medical bed including an adjustable side rail having intermediate positive stop positions between fully retracted and fully extended positions.
Still another object of the invention is to provide such an articulated medical bed having a control stick which facilities activation of the actuator by a disoriented occupant or one lacking good coordination skills or finger dexterity.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.